Even with her presidential hopes fading, Senator Hillary Clinton won a landslide victory in the West Virginia Democratic primary yesterday, renewing doubts about Senator Barack Obama's prospects in states with large concentrations of white, working-class voters.

"John McCain has decided that he is running for George Bush's third term in office," Obama told garment workers. "He has opted for the same approach that has failed the American people."

McCain's campaign responded by charging that Obama "debuted his 2008 attack playbook showing more of the same negative, partisan politics that have paralyzed Washington for too long."

With only five nomination contests remaining, Obama holds sizable leads in total delegates and the popular vote, and plans to declare victory in the pledged delegate contest after an expected win in Oregon next week. He moved closer to clinching the nomination with his big win in North Carolina and narrow loss in Indiana last week. Since then, Obama has taken the lead among superdelegates, the party leaders and elected officials whose votes will almost certainly determine the nominee. He added four more yesterday, for a total of 30 in the last week, more than the 28 delegates at stake yesterday in West Virginia.

The Illinois senator has begun all but ignoring Clinton to focus on McCain, believing he must start engaging with the Arizona senator and introducing himself to the wider general election electorate. One measure of Obama's dismissal of the West Virginia results was his decision not to speak after the polls closed last night, as has been customary in past primaries.

Continuing his first tour of general election states, Obama today is scheduled to make three stops in Michigan, including Macomb County, which came to represent "Reagan Democrats," working class white voters who deserted the Democratic Party in 1980. Next week he is scheduled to travel to Florida, another fall battleground.

Clinton and Obama both plan to campaign in the coming days in Oregon, where 52 delegates are at stake in the state's Tuesday primary; 51 delegates will be awarded in Kentucky. The final three contests are Puerto Rico, which votes June 1, and Montana and South Dakota, which vote June 3.

Last night, Clinton declared, "I am more determined than ever to carry on this campaign until everyone has had a chance to make their voices heard."

But nowhere will the voter demographics be as conducive to a big Clinton victory as West Virginia.

According to preliminary results of exit polls, 4 in 10 West Virginia voters were over age 60, and nearly all voters were white; about 7 in 10 lacked a college degree - the highest proportion yet in any Democratic primary; and the electorate had among the lowest family incomes.

The exit polls, conducted for the Associated Press and television networks, also offered more evidence of the deepening divide between Obama and Clinton supporters. Only a third of Clinton voters said they would definitely support Obama over McCain in the fall, while half of Obama's supporters said they would vote for Clinton.

Still, Clinton's win could help on a few scores.

First, it helps Clinton cut into Obama's lead in the overall popular vote, which had stood at more than 700,000 votes. The victory could also persuade the state's uncommitted superdelegates to follow the will of their constituents and support Clinton. And it could bolster her case to be Obama's running mate, which, according to a USA Today/Gallup poll published yesterday, is something 55 percent of Democrats - and nearly three-fourths of Clinton supporters - said they want to see.

John Edwards, who remained on the West Virginia ballot despite withdrawing in January, had 7 percent.

Top Democrats in the state said the result was not necessarily grim news for Obama in November if he is the nominee.

"The great majority of folks are proud of the Democrats running and are going to vote that ticket in November," said Nick Casey, chairman of the state Democratic Party, who is an uncommitted superdelegate.

Casey said that the Clintons, dating back to Bill Clinton's first campaign in 1992, have a long history with West Virginia voters. He said that while Obama is well-liked, he is simply not as well-known.

Still, Obama's campaign knows that if he wins the nomination, he will have work to do winning over the blue-collar crowd.

"He has got to make sure that people outside of Democratic strongholds understand he is somebody who loves his country very much and will fight for the middle class," Senator Claire McCaskill of Missouri, who accompanied Obama to Cape Girardeau, said yesterday, according to the Associated Press.